Stimulate Your Compost

Get out and dig to be ready for spring

By Dr. Francis Gouin

If you did a good job of building your compost pile last fall, now is a good time to stimulate more microbial activity.
Just before Christmas, temperatures in my compost pile dropped below 100 degrees from a high of 130 degrees measured just three weeks earlier. This falling temperature is due partially to a drop in surrounding ambient air and partially to a lower rate of microbial activity.
Microbial activity in composting can fall because of low levels of oxygen, excessive dryness, less available carbon or fewer sources of nitrogen. For most home composting projects, low levels of oxygen are unlikely unless your compost pile is taller and wider than 12 feet. Exchange of gasses is likely to be fine as leaves are bulky and do not pack easily. Thus, compost cooling is most likely due to a sudden drop in ambient air or dryness.
To check for moisture, thrust your hand into the compost and squeeze firmly. If the composting waste feels wet like a sponge, there is adequate moisture. If the compost feels on the dry side, drag out the hose and wet the pile down with a heavy stream of water. After the compost appears adequately wet, use either a grub-hoe or digging spade, going as deep into the pile as possible while adding more water. The excess water will drain deeper into the composting mass. If possible, empty the composting bin and wet the waste before re-filling the bin. Digging into the composting materials will grind the larger particles into smaller pieces, stimulating greater microbial activity. Ground leaves compost faster than whole leaves.
Within a week after you’ve reformed the pile, temperatures within it should increase. However, if your compost pile is less than three feet by three by three, it is not likely to give you much temperature rise due to a lack of mass.